COCO的格式不利于查看，因此下面代码是读取只提取单张图的标注信息：
# -*- coding:utf-8 -*-
from __future__ import print_function
from pycocotools.coco import COCO
import os, sys, zipfile
import urllib.request
import shutil
import numpy as np
# import skimage.io as io
import matplotlib.pyplot as plt
import pylab
import json
json_file='person_keypoints_train2017.json' # # Object Instance 类型的标注
# person_keypoints_val2017.json # Object Keypoint 类型的标注格式
# captions_val2017.json # Image Caption的标注格式
data=json.load(open(json_file,'r'))
data_2={}
data_2['info']=data['info']
data_2['licenses']=data['licenses']
data_2['images']=[data['images'][27]] # 只提取第一张图片
data_2['categories']=data['categories']
annotation=[]
# 通过imgID 找到其所有对象
imgID=data_2['images'][0]['id']
for ann in data['annotations']:
if ann['image_id']==imgID:
annotation.append(ann)
data_2['annotations']=annotation
# 保存到新的JSON文件，便于查看数据特点
json.dump(data_2,open('./new_instances_val2017.json','w'),indent=4) # indent=4 更加美观显示结果：
{
"info": {
"description": "COCO 2017 Dataset",
"url": "http://cocodataset.org",
"version": "1.0",
"year": 2017,
"contributor": "COCO Consortium",
"date_created": "2017/09/01"
},
"licenses": [
{
"url": "http://creativecommons.org/licenses/by-nc-sa/2.0/",
"id": 1,
"name": "Attribution-NonCommercial-ShareAlike License"
},
{
"url": "http://creativecommons.org/licenses/by-nc/2.0/",
"id": 2,
"name": "Attribution-NonCommercial License"
},
{
"url": "http://creativecommons.org/licenses/by-nc-nd/2.0/",
"id": 3,
"name": "Attribution-NonCommercial-NoDerivs License"
},
{
"url": "http://creativecommons.org/licenses/by/2.0/",
"id": 4,
"name": "Attribution License"
},
{
"url": "http://creativecommons.org/licenses/by-sa/2.0/",
"id": 5,
"name": "Attribution-ShareAlike License"
},
{
"url": "http://creativecommons.org/licenses/by-nd/2.0/",
"id": 6,
"name": "Attribution-NoDerivs License"
},
{
"url": "http://flickr.com/commons/usage/",
"id": 7,
"name": "No known copyright restrictions"
},
{
"url": "http://www.usa.gov/copyright.shtml",
"id": 8,
"name": "United States Government Work"
}
],
"images": [
{
"license": 2,
"file_name": "000000368402.jpg",
"coco_url": "http://images.cocodataset.org/train2017/000000368402.jpg",
"height": 427,
"width": 640,
"date_captured": "2013-11-14 22:22:42",
"flickr_url": "http://farm8.staticflickr.com/7234/6912194164_60704b897c_z.jpg",
"id": 368402
}
],
"categories": [
{
"supercategory": "person",
"id": 1,
"name": "person",
"keypoints": [
"nose",
"left_eye",
"right_eye",
"left_ear",
"right_ear",
"left_shoulder",
"right_shoulder",
"left_elbow",
"right_elbow",
"left_wrist",
"right_wrist",
"left_hip",
"right_hip",
"left_knee",
"right_knee",
"left_ankle",
"right_ankle"
],
"skeleton": [
[
16,
14
],
[
14,
12
],
[
17,
15
],
[
15,
13
],
[
12,
13
],
[
6,
12
],
[
7,
13
],
[
6,
7
],
[
6,
8
],
[
7,
9
],
[
8,
10
],
[
9,
11
],
[
2,
3
],
[
1,
2
],
[
1,
3
],
[
2,
4
],
[
3,
5
],
[
4,
6
],
[
5,
7
]
]
}
],
"annotations": [
{
"segmentation": [
[
211.96,
346.66,
207.4,
265.33,
220.2,
253.45,
202.83,
238.82,
203.74,
183.99,
225.68,
162.97,
220.2,
137.39,
230.24,
114.54,
253.09,
100.83,
273.19,
107.23,
283.25,
134.64,
287.82,
153.84,
284.16,
171.19,
299.7,
178.51,
299.7,
219.63,
246.7,
221.46,
247.61,
243.39,
289.65,
248.88,
290.56,
272.64,
214.71,
349.4
]
],
"num_keypoints": 15,
"area": 14801.0467,
"iscrowd": 0,
"keypoints": [
255,
136,
2,
263,
131,
2,
249,
132,
2,
272,
138,
2,
235,
138,
2,
286,
187,
2,
219,
181,
2,
294,
234,
1,
213,
242,
2,
317,
227,
1,
223,
220,
2,
279,
278,
2,
229,
280,
2,
276,
358,
1,
243,
366,
1,
0,
0,
0,
0,
0,
0
],
"image_id": 368402,
"bbox": [
202.83,
100.83,
96.87,
248.57
],
"category_id": 1,
"id": 476223
}
]
}